This invention is directed to a screen filter device for removing solid particles from a liquid for purposes of separating the solid particles out for recovery and/or cleansing the liquid for recirculation. The general category of filter device to which this invention is directed includes those in which a spray or shower is used to clean the filter media.
There are many such devices available in the art such as for example that shown in U.S. Pat. No. 3,112,263. In that device the screen filter is fitted with a sloping screen and the liquid to be filtered is flowed over the screen radially towards the center. Impurities are removed from the screen by a shower of liquid directed upwards and through the screen from beneath.
There are many problems with such a device which is typical of the art. For example it has been thought that to properly unplug a screen seal from above the spray must be directed from beneath. This has resulted in the fines dropping back on the source of the spray such as on nozzles rotating beneath the screen, thereby loading the arms. Additionally, the spray from below must pass through the screen raising pressure requirements to the possible extent of the spray raising or lifting the screen unless additional steps are taken to fasten it securely against vertical-upward displacement.
The present invention is intended to be an improvement over the art as represented by said U.S. Pat. No. 3,122,263.